TIME LOOPS

Wait, haven't you read this page before?

Ever since I was young I've had this fascination with time travel. But there's a ton of sites out there already dedicated to that sort of thing, so I'm going to concentrate here on one thing in particular, namely time loops. That is, the idea of reliving a day (or other particular length of time) over and over and over again.

Just for the heck of it, I've decided to try and compile together a list of instances when this has occurred, and how the writers dealt with the phenomenon (in at least some detail). Note that using time travel to simply repeat an instance of time doesn't count; sure, Marty McFly lived through November 12, 1955, on two occasions, in the Back to the Future trilogy... but he was a separate person each time and able to alter his prior actions.

The list is chronological, with the exception of putting "Groundhog Day" first... the Star Trek: TNG episode actually aired BEFORE this well known movie. I am also aware of the cancelled series "DayBreak" (2006), where a time loop was the main plot point (Detective Hopper keeps repeating the same day, with his injuries carrying over to the start of the loop). In fact, after seeing only two episodes, I had issues with the lack of a reason and limited potential character development myself. "Russian Doll" (2019) seems to have done better, but I haven't seen that.

Oh, one more thing. In March 2003, the group Improv Everywhere created a real life twelve iteration time loop, in a Manhattan Starbucks, as a prank. You can read about how well that went on their website here, and it is also apparently part of their book.

The more well known instance of time looping, which usually gets referenced when there's a discussion on the subject. Phil Connors (Bill Murray), a TV weatherman, keeps repeating the same February 2nd over and over.

• Trigger: Divine intervention.
• Who knows: Only Phil.
• Looping period: One day (Feb 2).
• Time passing outside of loop: No indication of such.
• How the loop is broken: Phil must better himself as a person and perform certain humanitarian acts for others.
• Random remarks: Suicide didn't break the loop.

• Trigger: Meglos traps the Doctor's TARDIS in a chronic hysteresis.
• Who knows: Meglos and cronies; The Doctor and Romana.
• Looping period: About a minute.
• Time passing outside of loop: Yes, Doctor delayed in reaching Tigella.
• How the loop is broken: The Doctor and Romana deliberately repeat their actions before the loop restarts, phase canceling the hysteresis.
• Random remarks: Romana's "Oh blast, here we go again", which begins the loop, originally referred to repairs on K9.

• Trigger: The Enterprise blows up near a highly localized distortion of the space-time continuum.
• Who knows: No one. Realization comes from a sense of deja vu.
• Looping period: Unspecified; several hours.
• Time passing outside of loop: Yes. Chronometers are off after emerging.
• How the loop is broken: They are able to send a message into the next loop advising of the proper action.
• Random remarks: Dr. Crusher is unable to avoid breaking a glass every time through the loop.

• Trigger: Neron was granted a wish since his love Hermia committed suicide, and he wished for the day never to end.
• Who knows: Xena and Neron (though Neron never spoke up until the end).
• Looping period: One day.
• Time passing outside of loop: No; Gods seemed to take care of that.
• How the loop is broken: Xena learned enough about the town history to prevent the suicide and avert a family feud.
• Random remarks: The rooster was not harmed during the production of this motion picture.

• Trigger: A glitch in the Backstep makes Frank Parker loop back to his arrival time.
• Who knows: Only Frank.
• Looping period: Five hours.
• Time passing outside of loop: No (as with any Backstep).
• How the loop is broken: After a few loops, Ballard fixes the glitch.
• Random remarks: When Olga dies (after the fix), the problem becomes how to ensure another loop.

• Trigger: A man (Bernard) blows up a bank with a bomb.
• Who knows: Bernard's girlfriend, Pam. She attempts to consult with Mulder and Scully.
• Looping period: Possibly the entire Monday, possibly just the morning.
• Time passing outside of loop: No indication of such.
• How the loop is broken: Mulder is able to send a reminder to himself in the next loop, which allows events to occur differently.
• Random remarks: The FBI agents are unable to avoid going to the bank.

• Trigger: The demon Tempus says he will help Rodriguez kill the three Charmed Ones by replaying Wednesday until he succeeds.
• Who knows: Tempus, Rodriguez, and Phoebe.
• Looping period: Wednesday morning until after 6pm.
• Time passing outside of loop: No.
• How the loop is broken: Prue casts a spell to speed up time, pushing them beyond the loop.
• Random remarks: A premonition of Andy's death was only fulfilled in the timeline that continued on without looping.

• Trigger: Dr. Mark Crest is testing a nuclear powered teleportation device, which misfires.
• Who knows: Dr. Crest, and later colleague Dr. Cleo Lazar.
• Looping period: Varies; starts at one day, grows smaller each time.
• Time passing outside of loop: No indication of such.
• How the loop is broken: Dr. Crest prevents a saboteur from fiddling with his device.
• Random remarks: Features a different start point for each loop as well as the power to give someone else the knowledge that the loop is occurring.

• Trigger: A man (Malikai) activates an ancient alien computer on planet P4X-639.
• Who knows: Malikai, Jack O'Neill and Teal'c, who were all caught in the field.
• Looping period: Ten hours.
• Time passing outside of loop: Yes. Earth's stargate was unavailable for dial-in for at least 3 months.
• How the loop is broken: O'Neill and Teal'c learn enough to be able to reprogram the alien computer.
• Random remarks: A fan favourite, it features inevitable Froot Looping, getting bashed by a door, and interdimensional golf.

• Trigger: The Gua have created a quantum pocket "prison" where time loops.
• Who knows: No one. Realization comes from premonitions.
• Looping period: Nineteen minutes (and a bit).
• Time passing outside of loop: Yes (outside pocket).
• How the loop is broken: Luck. Static charge of Cade's entry makes radio broadcasts and video surveillance report the previous loop, allowing them to send themselves a message.
• Random remarks: Cain enters the pocket mid-episode, and replaces Joshua in the car as he tries to bring Cade to an exit point.

• Trigger: A spell is cast on Buffy partway through the episode.
• Who knows: Buffy, Jonathan (spellcaster), caster's two geek cronies.
• Looping period: A few minutes.
• Time passing outside of loop: No.
• How the loop is broken: Buffy finally satisfies a customer trying to purchase a mummy hand.
• Random remarks: The geeks compare Buffy's time loop to the ones from Star Trek: TNG and The X-Files.

• Trigger: Proximity to a strange ship of the future.
• Who knows: Ultimately, everyone involved.
• Looping period: Seems to be a minute or two.
• Time passing outside of loop: Yes. Archer and Reed keep looping during a battle.
• How the loop is broken: Characters move away from the ship (once the deja vu has kicked in).
• Random remarks: Similar to the Buffy episode, only a small part of the episode involves time looping.

• Trigger: A mutant with the power to relive the last x hours of her life keeps looping to prevent a bomb detonation.
• Who knows: Samantha, then Brennan.
• Looping period: Controlled by Samantha, grows shorter as she loses strength.
• Time passing outside of loop: No (mutant power).
• How the loop is broken: Samantha stops using her power (dies).
• Random remarks: Some similarities to the Outer Limits episode, but major characters also have varied deaths (then are "resurrected").

• Trigger: Vedran Astro Engineering Institute technobabble, altering a planet's gravitation.
• Who knows: Supposedly just Celine, yet Harper leaves himself a note!
• Looping period: Sunrise to sunset, yet main characters also experience night.
• Time passing outside of loop: It must, since 300 years of events occur; so how did the main characters join Celine's loop?
• How the loop is broken: Vedran Astro Engineering Institute technobabble, altering a planet's gravitation.
• Random remarks: The episode would make much more sense if everyone simply forgot Celine daily, yet somehow events in the bar repeat themselves too.

• Trigger: Dean's death causes Sam to repeat Tuesday.
• Who knows: Sam and the trickster (who caused it).
• Looping period: Varies; restarts whenever Dean dies, which keeps changing.
• Time passing outside of loop: Seems not.
• How the loop is broken: The trickster is confronted - then must be found again when Dean dies on Wednesday.
• Random remarks: Refers to Groundhog Day, this being "too X-Files" and has music from Back to the Future on the radio.

• Trigger: A particle decelerator reverses the universe.
• Who knows: Jack Carter and Leo Weinbrenner, isolated by special light.
• Looping period: Ten hours.
• Time passing outside of loop: No "outside", this time wave is destroying reality.
• How the loop is broken: Leo's work is continued by groom Nathan Stark, after Carter sings a formula to convince him.
• Random remarks: The World Health Organization makes for a Doctor WHO reference.

• Trigger: Haruhi Suzumiya. Subconsciously.
• Who knows: Nagato. But by the 15,498th loop (after 594 years), deja vu has helped Koizumi, Mikuru and Kyon figure it out too.
• Looping period: August 17th to August 31st, midnight.
• Time passing outside of loop: No "outside", September has disappeared, even Mikuru can't time travel forwards.
• How the loop is broken: Kyon needs to do something to ensure Haruhi has no regrets about the end of summer.
• Random remarks: Each episode restarts the loop but despite this being an animated series, they didn't reuse frames - different loops meant different clothing, perspectives, etc.

• Trigger: A message from Kai prompts Dr. Tom to place Erica in a loop.
• Who knows: Erica and Dr. Tom; for six loops, Adam does too.
• Looping period: From 8am until noon, occasionally less.
• Time passing outside of loop: No. (Time travel therapy.)
• How the loop is broken: On the eleventh run, Erica manages to deal with what Kai said about the future.
• Random remarks: A guy gets incredible news on his phone a few times.

• Trigger: Aliens.
• Who knows: Bill Cage, then Rita Vrataski.
• Looping period: Varies; restarts whenever Cage dies, which keeps changing.
• Time passing outside of loop: No.
• How the loop is broken: Blood transfusion.
• Random remarks: Based on a Japanese light novel, "All You Need Is Kill" (2004) that became a manga.

• Trigger: Strange's Eye of Agamotto.
• Who knows: Strange and Dormammu.
• Looping period: Varies; restarts whenever Strange dies, which keeps changing.
• Time passing outside of loop: No, because time was frozen on Earth.
• How the loop is broken: Dormammu bargains.
• Random remarks: It's hypothesized that Strange spent many years in the loop.

• Trigger: Harry Mudd uses a time crystal.
• Who knows: Mudd and Stamets (who has tardigrade DNA).
• Looping period: 30 minutes
• Time passing outside of loop: No.
• How the loop is broken: Stamets gets Burnham to outcon Mudd.
• Random remarks: Mudd claims he killed Lorca 53 times (~ 3 loops before the end).

Other sites about time loops:
http://en.wikipedia.org/wiki/Time_loop
http://www.crownedanarchist.com/timeloop.htm
http://www.mjyoung.net/time/ (for infinity loops)
http://tvtropes.org/pmwiki/pmwiki.php/Main/StableTimeLoop (for causality loops)

Other loop sites that link here thus allowing you to loop back:
The Shapiro Files: Of ... Time-Looping Films
Let's Do The Time Loop Again. And Again...
Halfbakery: Time Loops Game
Models of Time and Fate (ok, I wrote that)